Camera shutter, including adjustable flash synchronizing means



May 13, 1952 c, c, R T 2,596,671

CAMERA SHUTTER, INCLUDING ADJUSTABLE FLASH SYNCHRONIZING MEANS FiledSept. '7, 1949 3 Sheets-Sheet l O 46' 1012/4/6/820222426 MILL/SECONDS 9l3 l5 l7 l9 CARL C. FUERST INVENTOR amm 011a C- C. FUERST May 13, 1952CAMERA SHUTTER INCLUIiING ADJUSTABLE FLASH SYNCHRONIZING MEANS 3Sheets-Sheet 2 Filed Sept. 7, 1949 CARL C. FUERST INVENTOR away/ BYTTORNE S C- C. FUERST May 13, 1952 CAMERA SHUTTER, INCLUDING ADJUSTABLEFLASH SYNCHRONIZING MEANS Filed Sept. 7, 1949 5 Sheets-Sheet 3 CARL C.FUERST Patented May 13, 1952 N lTED is TATiE S PAT E NT F etc-E2,596,671 CAMERA-SHUTTER, INCLUDING "ADJUST- ""'FI2ASH SYNCHRO NIZINGMEANS "Carl C. Fuerst, Rochester, N. Y.,jassignor toEastman KodakCompany,- Rochester, N. -Y a cor- .vporation of NeW'Jer'seyAiipliatidNSBflfehtber 7, 1949, SeiiaI No. 114,375

.The 1 present invention relates to a flashlight synchronizing mechanismbuilt into a ;photo graphic shutter, and. particularly to asynchronizin'g mechanism of this type in which the time delay betweenclosing of "the lamp circuit and opening of the shutter is automaticallyadjusted to givethe best "possible light and speed combination forany-speed setting of the shutter.

Conventional non-repetitive fiashlamps are available inseveral types,the types :generally being distinguished'by the burning characteristicsof the lamps. So far as the: present inventionis concerned, the onlytwotypes of larnps of interest are the type having substantially a 20-22millisecond lag, and thetype having substantially-a millisecond -lag."The first-mentioned type of flashlamp produces a hi'ghe'r, peakillumination than the otherand has a light. curve extending over a muchgreater time duration, as will be set forthinmore detail hereinafter."In otherwords, the lamps with a 22millis'e'cond lag come to peakillumination-more. gradually, having a wider peak, and 'dieoutmorefg'radually than lamps having a5 millisecond lag. Flashlamps;having a 2o 22 niillisecond "nag" "characteristic include :those on themarket and designated as =type s #5, #11, #25, #f40, #42,jetc;; these:number designations being used by "different-lamp manufacturers.

Lamps havinga5 irnillis'econd tlag' c aracteristic includethe'SMflasmamp manufactured by GeneraLEIectric,Conipany. In o'r'derto'readily-identify these different types of fiashlainps according to theirburning "characteristics" without referringv to manufacturers tradenumbers, the AIT S, A! has setup s'pecificationsgi'ouping thesedifferent types o'f' fla shlamps i according to classes. According toAQS. "Specification 1"Z '-'52.43-l 944 all non repetitiveflashlampshaving substantially a 20422 millis'econd la'g and the widecharacteristic "light curve," are"desig'- nated as class M lamps;regardless "ofman'ufactui erdesignation. f'lhosej am s havingsubtantiallya 5 millisecond flag'! are designated as class 'Ff lamps.Accordingly, throughout; the present specification and claims, these twodiffe'r entitypes er flashlamps will be referred'to as class M and classFflamps; the"class"" M lamps includingfthose typeshaving substantially a"20 22 millisecond lag and relatively long light-emittingcharacteristics, while the class "F lamps include those types having ashorter substantially 5 millisecond lag and a relatively steep lightcurve, orone' of short duration.

"Conventional flash synchronizers cnthe= market'toda'y are only adjustedin accordance-with isfoiiim's. (01. 95-115) the lag" charact'eristic ofithe differentclasses of lamps adapted i to: be used withoutanyconsideration as to ishutters'peed to' be used. For instance,ifraisynchronizer is? to be" used only with class M" ifiashla'mps, it isusually adjusted $0 insure that the flash circuit iwillbe closed inproper ti'med' relation with operation of the shutter to insure theshutter being full-open when the" lampreaches itspeak of illumination.Such adjustments-are made 'to give th-issynchronization. at the:highest? shutter speed; of which the shutter is capable-because atthese: high speeds the-shutter isopen forthe shortest time. How'- ever,when synchronizers: so adjusted-amused at the slower-shutter speeds,thatpor-tion of Lthe lightemitted during the -time that -the lamp; iscoming upto peak is lost and the maximum light available is not used.With-class F? lamps', this loss ofuse oi light-at shutter speeds other;than that which the synchronizer is adjusted 'for is not so importantbecause ofthe steepor nair'row nature of the light curves for theselamps. Those synchronizers which are adapted to Iaccon'imodate b oth:class -M' and class "-F lamps, as/wen as others, are usuallyadjustedbetweenionly two or more positions, depending 'u cn "the'niifiiber ofdifferentclass lamps to 'belffacconi'r'nodatd, each adjustment', beingbasedi'solely onlthe 'lag characteristic of the lamps without regard "todifferent shutter speeds which might be used. While some shutters"haying built-in synchroni'zers -adjustable by means f'of'a; scaleitdafccjommodate bfoth classfM" and class F'ffiashlamps includeintermediate points on I the fadjusting scale by which the operator canmake anew ances-*for"shu'tter-"spe'd to -obtain="a'-'-better light andspeed combinationthan the syn'ch'ronize-r is primarily aldjusitedior,such adiustments arezieit to the judgment of the operator and: requirethat he will be completely familiaruwith theiburning characteristics :ofthe classi ofilampsx to be used, along -with the opening characteristicsof his shutter. Obviously; such adiustmentseare useful only tothe-advanced amateurprprofessional who takes; the trouble "to; acquainthimself with vthe technicalities of shutter operation (and "lamp burningcharacteristics,."an'd, even "then, the adjustments hemight make are"only a proximate and will not give the best possible'lightfand speedcombination.

One obj ectof thepte'serit invention is toprovide "a built-in flash*synchron-ize'r in" which the synchronizer is '-aut'omatica-lly adjlisted ""by ad-- j-ustnient ofthe shutter speed control member to givethe best possible light -and spe'ed' icombination for the class offiasnlampi torlbemsed.

Another object is to provide a built-in flash synchronizer of the typeset forth which is adapted to accommodate both class M and class Fflashlamps, and in which adjustment of the synchronizer according to theshutter speed is accomplished when using only one, or when using bothclasses of flashlamps.

A further object is to provide a built-in flash synchronizer of the typeset forth which is adjustable to accommodate both class M and class Fflashlamps, but in which further adjustment of the synchronizer as toshutter speed is accomplished only when using class M lamps and theoperative connection between the shutter speed control ring and thesynchronizer for making this last-mentioned adjustment is automaticallymade and broken as the synchronizer is adjusted to and from,respectively, a position to accommodate M" class lamps.

And yet, another object is to provide in combination with a built-inflash synchronizer of the type described, including an electrical switchadapted to be operated by the shutter mechanism in proper timed relationwith the opening of the shutter to produce the desired synchronizationof light and shutter opening, and wherein the shutter is adjusted tovary the time of closing thereof in accordance with the class flashlampused, an operative connection between the switch and speed control ringof the shutter by which the switch is further automatically adjusted inaccordance with the selected shutter speed to give the best possiblelight and speed combination.

The novel features that I consider characteristic of my invention areset forth with particularity in the appended claims. The inventionitself, however, both as to its organization and its methods ofoperation, together with additional objects and advantages thereof, willbest be understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich Fig. l is a front elevational view of a complete photographicshutter having a built-in fiash synchronizer constructed in accordancewith the present invention;

Fig. 2 is a graph showing the characteristic light curve for class F andclass M flashlamps, and showing an operating curve of the disclosedshutter superposed on the class M light curve to bring out the purposeand advantages of the novel adjustment of the synchronizer in accordancewith the shutter speed that I provide to obtain the best possible lightand speed combination for any selected shutter speed;

Fig. 3 is a front view of the shutter with the cover plate removed andshowing the operative connection between the flash switch and the speedcontrol ring of the shutter;

Fig. 4 is a front view of the shutter with the speed control ringremoved and showing the cam ring for adjusting the synchronizer toaccommodate different classes of flashlamps;

Fig. 5 is an enlarged detail of that part of the shutter including thescale for adjusting the synchronizer to accommodate different classes oflamps; and

Fig. 6 is an enlarged view of the shutter with the cover plate and otherparts removed to show the blade-operating mechanism of the shutter,along with the flash synchronizer particularly adapted for this type ofshutter-operating mechanism and in combination with which the presentinvention is adapted for use.

Like reference characters refer to corresponding parts throughout thedrawings.

Referring, first, to Fig. 2, the purpose and result of the presentinvention will be described in connection with the graphs of thisiigure. Looking first at the characteristic light curve for class .I.iiashlamps, it will be seen that for the first two milliseconds afterthe circuit of this class of lamp is closed, there is no appreciablelight emitted, and then the amount of light increases quite graduallyuntil the peak of illumination is reached at between 20-22 milliseconos.The peak remains at its maximum for not more than two milliseconds andthen the light gradually falls oif, taking more than 20 milliseconds todo so. In other words, this class of lamp is emitting some degree oflight for over 40 milliseconds.

superposed on this light curve of the class M lamps is a curve showingthe operating characteristics of a photographic shutter of the type inconnection with which my invention is disclosed. This curve ischaracteristic of all between-the-lens type shutters and differs frommost in that it includes a /800 speed, whereas most shutters only have atop speed of /200, or /400. The operating curve of the shutter istrapezoidal, the length of the top and bottom lines thereof varying withthe speed of operation. As indicated by the slope of the upright linesof the shutter curve, this shutter in question takes approximately twomilliseconds to reach a fullopen position after release and takes twomilliseconds to close from a full-open position. The only exception tothis is the /200 speed setting where an additional spring is added tothe bladedriving mechanism and the opening and closing times drop toabout one and one-half milliseconds each.

Looking at the shutter curve it will be noticed that when operated at aspeed of /z5th second, the shutter is fully open for approximately 40milliseconds, as indicated by the length of the top line bounded by theareas designated as brown. The full-open time of the shutter decreasesas the speed increases until the /800 speed is reached at which theshutter is only fully open for a little over one millisecond, this areabeing designated as red on the shutter curve. The fullopen time of theshutter for the different speeds will vary with the speed as indicatedon the curve; the /50 speed being designated as purple, the speed asyellow, the /200 speed as blue, and the /400 speed as green.

It will be understood that in order to function with the greatestefficiency, or to obtain the maximum available light at the top or /800speed, the synchronizer must be adjusted so that the lamp will be at atits peak during the one and one-half milliseconds that the shutter isfully open at this speed. Taking into account the one and one-halfmillisecond opening time of the shutter at this speed, this means thatthe synchronizer must be adjusted to close the lamp circuit about 19milliseconds before the shutter is tripped. This is the basis upon whichmost synchronizers are selectively adjusted by the operator, since theiradjustment is generally only to accommodate for different classes offlashlamps and not for shutter speeds in addition to the class lamp.

If the synchronizer when adjusted by the operator to use class M lampsis factory set to synchronize properly at only the t or other top speed,it will be apparent from an inspection of Fig. 2 that if slower shutterspeeds are used before the shutter is tripped, as is necessary toaccommodate the /800 speed, and'the shutter is operated at a slowerspeed, then all or a part of the light emitted by the lamp, up until-1treaches its peak, will be wasted, depending upon the shutter speed usedbecause the shutter is not open during the time the lamp is reaching itspeak. As a compromise, built-in synchronizers, adjustable to accommodatedifferent classes of flashlamps, can be initially adjusted sothat whenset for class M lamps they will close 'theswitch in timed relation totripping of the shutter so as to bring the shutter to fullopen positionat the highest speed slightly ahead of 1 the lamp reaching its peak.While this cuts down the maximum light available for operating at thehighest shutter speed, it makes it possible for the slower speeds to getin more of the light underthe rising portion of the light curve. Evenwith such a compromise, the best possible light and speed combinationsare not approached. Looking again at Fig. 2, it will be observed thatwhen a th shutter speed is used with class M- lamps, the shutter isfully open so long that it could embrace almost the entire light outputof the lamp if the delay time be tween switch operation and shuttertripping were reduced to '7 or 8 milliseconds. It also follows that inorder to make use of the most available light at r, of a second shutterspeed, the time delay should be 9-10 milliseconds; for a n speed a 11-12millisecond delay, and so on up to a maximum delay of 19 millisecondsfor a shutter speed. My present invention comprises a means wherebyconventional built-in synchronizers will be automatically adjusted bythe selective setting of the speed ring of the shutter to attain thedesired time delay between closing of the lamp switch and tripping ofthe shutter, giving the best possible light-speed combination.

Looking at the light curve of the class F lamps, it will be seen thatthis class of lamps reaches its peak of ilumination rather quickly,about milliseconds, and the useful light area under the curve is onlyabout 12 milliseconds in duration. Accordingly, for practically allshutter speeds, except the /3' if the shutter is tripped simultaneouslywith closing of the lamp switch, the shutter will be full-open toinclude the peak of illumination and will be open sufficiently long tomake use of substantially all the available useful light. Because of thelow light out ut of class "F lamps, as compared with class M lamps,class F lamps would not ordinarily be recommended for use with shutterspeeds as high as ,430 or 4 Accordingly, I have found it desirable tocorrect the delay time of the synchronizer in accordance with theshutter speeds only when using class M lamps, although from thefollowing description it will be obvious that the same adjustments couldbe provided and made available for class F" lamps, is desired.

For purposes of disclosing my present invention I have shown it incombination with a builtin synchronizer of the type fully described inmy copending application Serial No. 737,351, filed March 26, 1947, nowPatent No. 2,563,782, issued August 7, 1951, and in a, shutter having abla.de-

6 operating mechanism of the type shown in my copending applicationSerial No. 728,528, filed February 14, 1947, now Patent No. 2,524,786,issued October 10, 1950. Inasmuch as the flash synchronizer and shutterblade operating mechanism are fully disclosed in my above-notedcopending applications, only so much of the shutter blade operatingmechanism and the flash synchronizer per se will be described herein asis necessary to point out the operation and purpose of the presentinvention. I

The shutter, of which a synchronizer modified in accordance with mypresent invention forms a part, may appear as shown in Fig. 1. Asindicated, the shutter may consist of an annular casing i having a coverplate 2 surrounding a central exposure aperture3 and may contain fortensioning the operating spring. The cover plate includes a speed scale8 with which an index P on the face of a knurled flange 5 of a speedcontrol ring 30] see Fig. 3, cooperates. The cover plate is alsoprovided with a diaphragm scale 9 with which a pointer P on thediaphragm adjusting ring, not shown, cooperates. The cover plate is alsoprovided with a synchronizer adjusting means to make it possible for theoperator to adjust the synchronizer for use with the different classesof conventional non-repetitive fiashlamps having characteristic lags andfor use with repetitive type flash lam s having no lag, as exemplifiedby lamps of the gaseous discharge type.

As shown, this synchronizer adjusting means comprises a setting member10 which is fastened to an adjusting cam in the shutter, as will bedescribed, and which extends upwardly through and moves in an arcuateslot II in the shutter ter X, the synchronizer is adjusted for use withgaseous discharge type flashlamps having no lag,

but since this setting has nothing to do with the present invention,further description thereof and its functions will not be dealt withherein.

Essentially, the synchronizer, of which the present invention forms apart, comprises a se will be described herein sufficiently to point outthe features of the synchronizer which are aifected by the presentinvention. It is pointed out, however, that since the present inventionis not limited to use with a shutter mechanism of the type, describedand said shutter mechanism is completely disclosed in, my above-notedcopende ing application Serial No. 728,528, only so much. of

the mechanism per so will be disclosed herein as necessary to point outthe operation of the flash synchronizer with which the present inventionis combined.

As indicated in Figs. 4 and 6, the annular shutter casing may include anupstanding flange I5 extending around the periphery of the shutter; thisflange having a slot I6 formed therein to permit movement of the settinglever and havin a slot II permitting movement of the trigger 6 fortripping the shutter mechanism. As clearly set forth in my above-notedcopending application, and as indicated in Fig. 6, shutter blades I8 areof the symmetrical type, each blade being pivoted at I9 to the mechanismplate 20 and having an upstanding pin 2I extending through an elongatedslot 22 in an oscillat-able blade ring 23. This blade ring directlycarries an arm I which terminates in the setting member I and extendsthrough the slot I 5 in the flange I5. A power spring 25 is connected atone end directly to the blade ring 23 by a pin 25 and is connected atthe other end to a stud S carried by the shutter casing. Thus, thespring 25 acts directly on the blade ring 23 and it becomes tensionedwhen the setting member I is moved clockwise to the position shown inFigs. 3, 4 and 6.

As indicated in Fig. 6, the blade ring is held with the spring tensionedby means of a latch mechanism which consists of a first latch member 28pivoted on the stud 29 attached to the mechanism plate 20. The latch 28has a beveled end 3i and xtencls across the top of the shutter; and thislatch member lying beneath a second latch member 32 also pivoted on stud29. Latch 32 has a latch face 33 adapted to engage an outwardlyprojecting protuberance 34 on the setting lever i. This latch thereforeholds the setting lever I and the blade ring 23 in their set positionwhen the lug 34 moves up over the incline 35 of the second latch memberas the handle I is moved to a set position. A downwardly extendingflange 3S limits the unward movement of the second latch member 32 underimpulse of its spring 31, but it also permits the second latch to movedownwardly with respect to its Fig. 6 position and the first latchmember 28.

The first latch 28 includes the beveled surface 3I, above referred to;which normally lies in contact with a beveled surface 38 on the shutterreleasing member 39. This member may turn on a pivot 40 and includes apower spring I26 which by acting on pin i 53 fixed to and extendingabove member 39 tends to turn member 38 in a counterclockwise direction.When the beveled surfaces 3! and 38 engage, movement of member 33 isprevented because the engagement of these two surfaces is almost on deadcenter between the studs 40 and 29 on which the power-operated member 39and the first latch member turn. However, the trigger 6 can startmovement of the first latch member 28 and which movement may then becompleted by the power-operated member 39 in a manner completelydisclosed in m copending application Serial No. 737,351, abovementioned. It will suifice herein to say that there is a connectionbetween the trigger 6 and latch member 28 by which depression of thetrigger 6 causes latch member 28 to be depressed sufficiently to movethe beveled surface 3| out of dead center relation with beveled surface38, but by an insuflicient amount to actually trip the shutter. Thisfurther movement of latch member 28 is taken over by power-operatedmember 39 to actually release the shutter.

Coming now to the synchronizer with which the present invention iscombined and which is fully disclosed in my noted copending applicationSerial No. 737,351, fastened to flange I5 of the shutter casing is aterminal I H to which a mating connector on a flashholder, not shown,may be connected. The flashholder will include a source of potential anda flashlamp respectively, shown diagrammatically in Fig. 4 as B" and L,"and the terminal is such that one side of the flash circuit will begrounded to the shutter casing, while the other side will be connectedto the center post I ll of the terminal which is insulated from theshutter casing and extends to the interior thereof.

The switch for synchronizing conventional nonrepetitive flashlampshaving a lag" comprises a first contact which is the pin H0 carried bythe shutter release member 39 and a second and adjustable contact H5lying in the path of movement of the pin H6. The contact H5 is carriedby insulating member 200 which is, in turn, carried by an arm I I3pivoted on a stud I I4 fastened to the mechanism plate of the shutter.The arm H3 has an upturned lug 20I thereon which engages a cam surface II2 on the synchronizer adjusting ring I00 which is oscillatably mountedin the shutter below the cover plate and speed control ring and whichhas the adjusting member I0 fastened thereto. Contact I I5 iselectrically connected to the center post Ill of terminal III by aninsulated conductor H8 lying adjacent the interior of the flange I5 ofthe shutter casing and a conductor strip 203 fixed at one end to theconductor H8 and at the other end to a pin 204 on the arm H5. Conductorstrip 203 is made of a resilient metal and takes the form of a coilsprin so that it normally tends to pivot contact H5 in acounterclockwise direction and thus hold the lug 20I against the camsurface I I2.

Therefore, inasmuch as contact H5 is connected to one side of the flashcircuit through conductor H8 and pin H6 is connected to the other sideof the circuit by being grounded through the shutter casing, when pin II 6 engages contact I I5 the flashlamp circuit will be closed toenergize the lamp. Inasmuch as pin H6 is carried by the shutterreleasing member 39, it can be made to engage contact I I5 at anydesired time prior to the actual release of the shutter and inaccordance with the lag" characteristics of the fiashlamp to be used. Toobtain the desired delay between closing of the lamp circuit and therelease of the shutter, there is provided a gearretarding mechanismincluding a flywheel 205 having a pinion 206 fixed thereto which, inturn, engages a gear segment 20! on the arcuate end of member 39. Byadjusting the synchronizer ring [00 with the aid of member I0 and thescale I I, the position of contact I I5 relative to that of pin H6 onmember 39 can be varied to obtain a synchronization between the peak ofillumination of the fiashlamp and the full-open position of the shutterin accordance with class F" and class M" flashlamps. To allow the use ofrepetitive flashlamps of the gaseous discharge type which have no lag,this synchronizer may include a second switch in series or parallel withthe first switch which closes the instant the shutter blades reach theirfull-open position; means being provided to render the first switchinoperative when the second switch is used and this being accomplishedby adjusting synchronizer cam ring I00 to the "X" position on scale H.However, since this second switch does not enter into the presentinvention, it will not be described herein.

Coming now to the present invention, for reasons fully discussed aboveit is desirable to be able to adjust the firing time of the flash switchin accordance with the shutter speeds to be used, particularly whenusing class M lamps. To accomplish this, I attach a cam plate 300directly to the speed control ring 30I of the shutter to move therewith.As is customary in all betweenthe-lens type shutters, the speeds aredetermined by placing a retard action on the spring-driven bladeoperating member. As shown in Fig. 3, this is done in the presentshutter by pivoting a. double-ended lever302 on the mechanism plate sothat one end 303 thereof can move into the path of pin 26 on the,blade-operating ring 23 and will have to be cammed out of the way bymovement of the blade ring when moving through its operating stroke. Theother end of lever 302 includes a gear segment 304 which meshes with apinion 305 constituting one element of a gear train, the remainder ofwhich is not shown. The farther the nose 303 of lever 302 is allowed tomove into the path of the pin 26, the more retard action there is placedon the blade-operating ring and, hence, the slower the shutter speed.The position of the lever 302 is controlled by the speed control ring30I which includes an opening 306 through which a pin 30'! on the end304 of the lever 302 extends; said opening having a stepped cam surface308 against which the pin 301 is forced by a spring, not shown, normallyacting to move lever 302 in a counter-clockwise direction. In otherwords, the steps on cam surface 308 determine the position of nose303-01 lever 302 relative to the path of travel of pin 23 on blade ring23 and, consequently, the amount of retard action which is placed on theblade operating mechanism. As the speed control ring 30I is oscillatedin accordance with the speed scale 8 on the cover plate 2, the properstep of cam surface 308 is moved opposite pin 331 to give this desiredspeed. As will be clear from an inspection of Fig. 3, when the speedcontrol ring is set at /1 or't speed, the pin 30! will be confined in anarcuate portion 400 of the opening 306 so that the nose 303 of lever 302will be removed entirely from the path of pin 26- on the blade ring andno retard action will be imposed on the blade mechanism. The diiferencebetween ,4 and 170O speed is obtained in. this shutter by the automaticinclusion of a booster spring for the speed, but, since this is notessential to the present invention, this is notshown.

Looking now at Figs. 3 and 4, the speed control cam 30!! which isattached to the speed control ring 30I lies directly above thesynchronizer adjusting ring I30 so that when the ring I 33 is adjustedfor class M lamps, the lug 20I connected to switch contact 1 I5 ext ndsupwardly suihciently to engage cam 300. It will thus be seen that whenthe speed control ring is adjusted to give different shutter speeds,then earn 305 thereon will take over and adjust contact H5 relative tocontact II6 to vary the closing time of the switch. This cam 33B is socalc' lated as to adjust the flash switch to give the desired and bestpossible speed and light combinations as discussed above. For instance,if the shutter is set for time of a second speed, then the low point oft e cam 303 will be opposite the lug 28I to allow contact I I5 to moveclose to contact H6 and thus accommodate the maximum or 19-20millisecond lag of the lamp. In this position, the cam 360 is coplanarwith cam H2 and isessentially inoperative. However, as the speed controlring ismoved clockwise to give slower shutter speeds, cam 300 takes overfull control of lug 20I and contact II5 fromv the synchronizer cam I I2and keeps reducing the delay time between switch closing and shutterrelease until at a & speed the delay time is only about 7-8milliseconds. In the position shown in Fig. 3, the speed control ring isadjusted for speed and cam 300 has adjusted contact I I5 relative tocontact I I6 to give a 11-12 millisecond delay between closing of the,flash switch and release of the shutter.

It will be observed that when the synchronizer camv ring I00 isadjustedto accommodate class flashlamps that lug 25H of contact H5. is moved outof engagement with speed control cam 330 and is not affected byadjustment of the speed control ring. This is in accordance with thediscussion above to the effect that because of the flash characteristicsof this class of lamp, no adjustments as to shutter speed are reallyrequired. If it were decided, however, that such. adjust.- ments wereneeded, another speed cam, like cam 363 but with a different curve,could be added to the speed control rin to come into play when thesynchronizer was adjusted for class F" lamps. By virtue of the disclosedarrangement of parts, namely the disposition of cams H2 and 330, it willbe apparent that speed control cam 300 will be automatically broughtinto operative relation with lug 20I when the synchronizer is adjustedby cam II2 to accommodate class M lamps.

While I have shown and described my invention. in combination with aparticular form of between-the-lens type shutter and having a particularform of built-in flash synchronizer, it will be readily understood thatit could be applied to any form of flash synchronizer which is adjust-.able to accommodate the different classes of flashlamps. For instance,in US. Patent 2,319,086, Riddell, May 11, 1943, there is shown abuilt-in synchronizer including switch contacts 5| and 62,

the former being adjustable relative to the latter through the use ofcam I8 on control ring IT to adjust the time of relativeclosing of theflash switch with the opening of the shutter blades to accommodatedifferent classes of flashlamps. Furthermore, this patent shows ashutter and synchronizer combination wherein the flash switch isoperated by the opening movementof the blade driving means, rather thanby the operationof the sh tter release mechanism. It will be obviousthat the speed control ring of this shutter, not shown, could beprovided with a cam, like cam 300 in the pres nt disclosure, which wouldtake over and further adjust upstanding fin er I5 and, hence, switchcontact 5| when control ring Tl wasset for lamps havinga 20-millisecond"lag (class M) and thus further adjust the switch to obtain the bestpossible speed and light combination for this class of lamps inaccordance with the present invention.

Althoigh I have shown and described certain specific embodiments of myinvention, I am fully aware that many modifications thereof arepossible. My invention therefore is not to be restricted except insofaras is necessitated by the scope of the appended claims.

Having thus described my invention, what I claim is new and desire tosecure by Letters Patent of the United States is:

1. In a photographic shutter the combination with shutter blades; ablade operating mechanism for controlling the opening and closing ofsaid blades; a speed control member adapted to be selectively positionedto vary the speed of operation of a part of said blade operatingmechanism involved in the actual opening and closing or the blades; 8,flash synchronizer mechanism comprising a normally open switch adaptedto be connected into an electric circuit controlling the ignition of aflash lamp of the F class or M class; said switch arranged to be closedby a part of said blade operating mechanism in timed relation to theopening of said shutter blades thereby to accommodate for the lag" ofthe flash lamp to be used; said switch being adjustable to alter thetime of closing thereof relative to the blade opening movement of saidblade operatin mechanism; means for selectively adjusting said switch toadjust the time of closure thereof in accordance with the lagcharacteristic of either the F class or M class flash lamps; of meansfor further adjusting said switch to automatically alter the time ofclosure thereof in accordance with selected exposure speeds, andincluding mean operatively connecting said speed control member and saidswitch whereby said switch is adjusted by movement of said speed controlmember.

2. In a photographic shutter the combination with shutter blades; ablade operating mechanism for controlling the opening and closing ofsaid blades; a speed control member adapted to be selectively positionedto vary the speed of operation of a part of said blade operatingmechanism involved in the actual opening and closing of the blades; aflash synchronizer mechanism comprising a normally open switch adaptedto be connected into an electric circuit controlling the ignition of aflash lamp of the F class or M class; said switch arranged to be closedby a part of said blade operating mechanism in timed relation to theopening of said shutter blades thereby to accomodate for the "lag of theflash lamp to be used; said switch being adjustable to alter the time ofclosing thereof relative to the blade opening movement of said bladeoperating mechanism; means for selectively adjusting said switch toadjust the time of closure thereof in accordance with the lagcharacteristic of either the F" class or M class flash lamps; of meansfor further adjusting said switch to automatically alter the time ofclosure thereof in accordance with the selected exposure speed whenusing lamps of the "M" class, said last mentioned means including meansoperatively connecting said speed control member and said switch wherebysaid switch is adjusted by and in accordance with movement of said speedcontrol member; and means for automatically rendering said operativeconnection between said speed control ring and switch effective andineffective as said first mentioned or selective switch adjusting meansis moved to and from, respectively, the position to accommodate M classlamps.

3. In a photographic shutter the combination with shutter blades; ablade operating mechanism for controlling the opening and closing ofsaid blades; a speed control member adapted to be selectively positionedto vary the speed of operation of a part of said blade operating mechanism involved in the actual opening and closing of the blades; a flashsynchronizer mechanism comprising a normally open switch adapted to beconnected into an electric circuit controlling the ignition of a flashlamp of the F" class or M class; said switch comprising a pair 01'normally spaced contacts, one of said contacts adapted to be engaged andmoved into switch closing relation with the second contact by a part ofsaid blade operating mechanism when moving to open the shutter, meansfor selectively adjusting said second contact relative to the firstcontact to alter the time of closing of said switch in accordance withthe lag characteristics of class F" or class M lamps; of means forfurther adjusting said second contact to automatically alter the time ofclosure thereof in accordance with selected exposure speeds, andincluding a cam means moved by said speed control member and having itscurve operatively engaging said second contact to adjust said contact assaid speed control member is moved.

4. In a photographic shutter the combination with shutter blades; ablade operating mechanism for controlling the opening and closing ofsaid blades; a speed control member adapted to be selectively positionedto vary the speed of operation of a part of said blade operatingmechanism involved in the actual opening and closing of the blades; aflash synchronizer mechanism comprising a normally open switch adaptedto be connected into an electric circuit controlling the ignition of aflash lamp of the F class or M class; said switch comprising a pair ofnormally spaced contacts, one of said contacts adapted to be engaged andmoved into switch closing relation with the second contact by a part ofsaid blade operating mechanism when moving to open the shutter, meansfor selectively adjusting said second contact relative to the firstcontact to alter the time of closing of said switch in accordance withthe lag" characteristics of class F or class "M lamps; of means forfurther adjusting said second contact to automatically alter the time ofclosure of said switch in accordance with selected exposure speeds whensaid selective switch adjusting means is positioned to accommodate classM" lamps, and including a cam carried by said speed control member tomove therewith, the curve of said cam operatively engaging said secondcontact to control movement thereof relative to said first contact.

5. In a photographic shutter the combination with shutter blades; ablade operating mechanism for controlling the opening and closing ofsaid blades; a speed control member adapted to be selectively positionedto vary the speed of operation of a part of said blade operatingmechanism involved in the actual opening and closing of the blades; aflash synchronizer mechanism comprising a normally open switch adaptedto be connected into an electric circuit controlling the ignition of aflash lamp of the F class or "M class; said switch comprising a pair ofnormally spaced contacts, one of said contacts adapted to be engaged andmoved into switch closing relation with the second contact by a part ofsaid blade operating mechanism when moving to open the shutter, meansfor selectively adjusting said second contact relative to the firstcontact to alter the time of closing of said switch in accordance withthe lag" characteristics of class "F" or class M lamps; of means forfurther adjusting said second contact to automatically alter the time ofclosure of said switch in accordance with selected exposure speeds whensaid selective switch adjusting means is positioned to accommodate classM lamps, and including a cam carried by said speed control member tomove therewith, the curve of said cam operatively engaging said secondcontact to control movement thereof relative to said first contact, andmeans for automatically connecting and disconnecting said operativeengagement between said cam and second contact when said selectiveswitch adjusting means is moved to and from, respectively, the positionto accommodate class M lamps.

6. In a photographic shutter the combination with shutter blades; ablade-operating mecha nism for controlling the opening and closing ofsaid blades; a speed control member adapted to be selectively positionedto vary the speed of operation of a part of said bladeoperatingmechanism; a flash synchronizer mechanism comprising a normally openswitch adapted to be connected into an electric circuit controlling theignition of a flash lamp having a characteristic lag; said switcharranged to be closed by a part of said blade-operating mechanism intimed relation to the opening of said shutter blades thereby in order toaccommodate for the lag of said flash lamp; said switch being adjustableto alter the time of closing thereof relative to the blade-openingmovement of said blade-operating mechanism; of means for adjusting saidswitch to automatically alter the time of closure thereof in accordancewith the selected exposure speed, and including a cam connected to saidspeed control member to be moved by adjustment thereof, said camdirectly engaging a part of said switch to adjust the time of closingthereof.

7. In a photographic shutter the combination with shutter blades; ablade-operating mechanism for controlling the opening and closing ofsaid blades; a speed control member adapted to be selectively positionedto vary the speed of operation of a part of said blade-operatingmechanism; a flash synchronizer mechanism comprising a normally openswitch adapted to be connected into an electric circuit controlling theignition of a flash lamp having a characteristic lag, said switchcomprising a pair of normally spaced con tacts, one of said contactsadapted to be moved into engagement with the second by a part of saidblade-operating mechanism to close the switch in timed relation to theopening of said shutter blades in order to accommodate for the lag ofsaid flash lamp; said switch being adjustable to alter the time ofclosing thereof relative to the blade-opening movement of saidblade-operating mechanism; of means for adjusting said switch toautomatically alter the time of closure thereof in accordance with theselected exposure speed, and including a cam connected to said speedcontrol member to be moved by adjustment thereof, said cam connected tothe second contact of said switch to adjust the separation between itand said first contact to alter the time of closing thereof.

8. In a photographic shutter of the setting type the combination withshutter blades; a bladeoperating mechanism for controlling the openingand closing of said blades when moving from a cooked condition; arelease mechanism for releasing said blade-operating mechanism from itscocked condition; a speed control member adapted to be selectivelypositioned to vary the speed of operation of a part of saidblade-operating mechanism; a flash synchronizer mechanism comprising apair of normally spaced switch contacts adapted to be connected into anelectric circuit controlling the ignition of a flash lamp having acharacteristic lag; means for connecting one of said switch contacts tosaid release mechanism to be moved into engagement with the secondcontact upon movement of said release mechanism to a shutter-releasingposition and in timed relation with the release of said blade-operatingmechanism thereby; of means for automatically altering the relative timeof closing of said switch and the release of said blade-operating meansby said release mechanism to accommodate for the lag of the flash lampand the selected exposure speed, and includingan operative connectionbetween said speed control member and the synchronizer mechanism wherebythe time of closing of said switch relative to the release of saidblade-operating mechanism from a cocked condition is automaticallyadjusted by movement of said speed control member.

CARL C. FUERST.

CES CITED The following references are of record in the is of thispatent:

UNITED STATES PATENTS Number Name Date 2,298,107 Carr Oct. 6, 19422,429,972 Aiken Nov. 4, 1947 2,435,161 Schwarz Jan. 27, 1948 2,455,365Jenner Dec. 7, 1948

